Device for cutting-screw-threads.



J. R. SAYLOR. DEVICE FOR CUTTING SCREW THREADS APPLICATION FILED .mml,1912 Patented Oct. 1, 1912.

o I l k W f i v Z i UNITED STATESCPATENT OFFICE.

JOHN R. SAYIQOR. or POTTSTOWN, PENNSYLVANIA.

nnvicn For. CUTTING sonnw-rnnnnns.

Specification or Letters Patent.

To all whom it may concern: I Be it known that 1, JOHN R; SArLoR,- "acitizen of the United States, residing 1n Pottstown, county ofMontgomery,:St-ate of Pennsylvania, have invented certain Improvementsin Devices for Cutting Screw Threads, of which the following is aspecification.

My invention relates to certain improvements in dies or taps usingchasers, which are detachably secured to the body of the tool and whichare for the purpose of cutting an internal or an external thread- Theobject of the invention is-to construct the die or tap so that thechaser can be adjusted to present new cutting portions as the cuttingsurfacebec'omes worn.

My invention also relates to details of construction, which will befully described hereafter, reference being had to the accompanyingdrawing, in-which:-

Figure 1, is a sectional elevation illustrating my invention applied toa die for cutting external threads; Fig. 2, is a transverse sectionalview on the line 22, Fig. 1; Fig. 3, is a perspective view of theeccentric lock for securing the chasers in position; Fig. 4: is adetached. perspective view of one ofthe chasers; Fig. 5, is a detachedperspective view of one of the tapered adjusting blocks; Fig. 6, is aside view illus trating my invention as applied to a tapfor cutting aninternal thread;Fig. 7, is. a sectional view on the line 7-7, Fig. 6;and Fig. 8, is a view of a modification.

Referring to Figs. 1 to 5 inclusive ofthe drawing, A is the die held tothe spindle B in the ordinary, manner. In the present instance, thespindle has a flange b and the die has a flange a. The sleeve B has athreaded portion adapted to the thread. on the flange a, and an internalflange which overlaps the flange b, holding the twooparts rigidlytogether. 4 r

In the inner wall of thebodyA is a series of longitudinal slots 0/ inwhich are mounted the chasers C, shaped as shown in Fig. 4, each havinga toothed face 0. These teeth are slightly backed off in the ordinarymanner so as to present a sharp .cutting point at the forward side ofthe chaser.

Within the body is a lock D consisting of a cylinder D having a ring Dsecured. to the upper end of the body by a threaded joint and held by apin cl. On the opposite end of this look is a series'ofeccentricseggreater than the width of the chasers. The periphery of eachsegment has l a thread corresponding to the thread on-the face 0 of eachchaser. This face is eccentric so that as the lock is turned and whilethe.

threadsengage the threads on the. chasers, the look also forces thechasers against, the rear of the slot in the body A locking them firmlyin position and, as the thread is con- Patented Oct. '1, 191 2.Application filed April 11," 1912. Serial No. 690,103.

inentsd separated bylnotc'hes d of a width i tinuous throughout theseveral sections, it adjusts each chaser so that they will track 7properly to cutv a thread; The eccentric lock can be turned by asuitable tool inserted inthe chaser, which-,in the present instance,

has notches e on its: inner wall. with which engages the projections ona wrench or other tool. I preferably make the eccentric lock hollow, asit is desirable, in some instances, to extend a tap or cutter through ithe die, although, in some instances, th eccentric lock may be solid.

At the lower end of the body, oppositethe flange a, is a threadedportion a", and adapted to this threaded portion is a ring H having aninternal flange provided with a beveled faceh,,whioh rests against thebeveled face 9 of blocks G adapted to slots 1 in the body portiondirectly back of each chaser C, so. that, .upon turningthering in onedirection, the blocks will force the chasers toward the center and willrelieve the chasers when the ring is turned in the reverse direction.Thus, as the teeth of the chasers 'wear, the chasers can be set up tocompensate for the wear. i

Chasers, when in use, wear rapidly at theouter end; the wear takingplace mainly on the first and second teeth. By my device the chasers canbe readily withdrawn from' the die and the ends ground soas, to

remove the first and second teeth; the chasers being re-adjusted in thedie and locked therein in the newposition after be ing moved forward adistance equalto the length of the toothed portion removed; as n longstheir life and lessens the cost ofthe,

cutting operation. InYFigs. 6 and 7, I- haveillustrated my nvention asapplied toa tap-=using de-" V tachablechasers. A" is the body portion ofthe tap having a series of longitudinal grooves in its periphery and inthese grooves are the chasers C. The body portion is arranged at aslight taper so that the threaded portion of the article to be actedupon will be slightly tapered. The invention can also be used 1nconnection with a I tap in which the body portion is not tapered.

D is an eccentric lock, preferably secured to the body portion A, asshown, and this look has an internal thread interrupted by the recess6Z3. This threaded surface is eccentric and bears against the edge ofthe chasers, as shown in Fig. 7, so that when "the lock is turned in onedirection, the

- a tapered plug I, which is provided with chasers in the adjusted.

a head or other device by which it can be turned, so that when the plugis turned in one direction the segments of the lock are forced againstthe chasers, firmly securing them to the body portion. lVhen the plug isturned in the opposite direction, the segments are released frompressure, moving clear of the chaser so that the chasers can bewithdrawn and readjusted.

In this construction it is not necessary to provide the lock with slotsto allow for the removal of the chasers.

I claim:

1. The combination in a device for cutting screw threads, of a bodyportion; a series of chasers arranged in the body portion; with alocking device having an eccentric'threaded portion engaging the teethof the chasers and confining the chasers to the body portion. I

2. The combination in a device for cutting screw threads, of a bodyportion having longitudinal slots therein; a locking device confinedlongitudinally to the body portion and a'llowed tov turn freely therein;said lock having an eccentric threaded portion; with-chasers located inthe slots of the body portion and having teeth on one face; said lockengaging-the teeth and retaining the positionv to which they are 3. Thecombination in a device for out: tingscrew threads, of a body portionhaving longitudinal slots therein; chasers mountedin the slots; with alock having a flange at one end engaging the body portion so as toprevent the lockfrom moving longitudinally, but allowing it to turnfreely therein; the opposite end of the lock having a series of segmentsspaced apart a distance equal to the width of the chasers and having ascrew threaded cut thereon; the screw threaded portion being eccentricso that when the lock is turned in one direction it will bind thechasers to the body portion, and when moved in the opposite directionthe space in the lock will be opposite the chasers so that the saidchasers can be moved or adjusted in the body portion.

4. The combination in a device for outting screw threads, of a hollowbody portion having longitudinal grooves in its inner walls; chasersmounted in the grooves; the threaded surface of the chasers projectingbeyond the wall of the body portion; with a lock mounted within the bodyportion and having a threaded section engaging the toothed surface ofthe chasers and acting to retain the chasers in position in the bodyportion.

5. The combination in a device for cutting screw threads, of a hollowbody portion having longitudinal grooves in its inner walls; chasersmounted in the said grooves, the threaded surface projecting beyond thewalls of the body portion; with a lock mounted within the body andhaving an eccentric portion engaging the teeth on the chasers.

6. The combination of a hollow body having longitudinal slots therein; aseries of chasers mounted in the slots in the hollow body; a locklocated within the body and held therein against longitudinal movement,but free to turn and having a series of segments spaced apart andthreaded on their peripheries; said segments being eccentric so thatwhen the lock is turned they will engage and hold the chasers in thebody.

7. The combination of a body having a series of longitudinal slots inits inner wall and recessed at one end; a lock having a flange adaptedto the recess; a series of chasers mounted in the slots of the body;said lock having at the end opposite the flange a series of eccentricsegments spaced apart; each segment having a threaded surface arrangedto engage the teeth on the chasers, whereby the chasers can be held inthe position in which they are adjusted.

8. The combination in a device for cut ting screw threads, of a body; aseries of longitudinally arranged chasers; means for locking the chasersto the body; a sliding block located in the body back of the forward endof each chaser; with means for actuating the blocks to move the chasersso as to take up the wear.

9. The combination in means for cutting screwthreads, of a hollow bodyhaving longitudinal grooves in its inner wall' a chaser in each groove;a look within the body engaging the chasers and holding them in theposition to which they are adjusted said body having a transverseopening back of each chaser near the forward end; with blocks mounted inthe transverse openings; said blocks being beveled at the rear; with ascrew threaded ring adapted to the thread on the body and having abeveled surface bearing against the blocks, so that, upon turning thering, the blocks will force the chasers toward the center of the body. 7

10. The combination in a device for cutting screw threads,of a hollowbody portion having longitudinal grooves in its inner wall and having anannular recess at one end; a chaser mounted in each groove; a lockhaving a flange mounted inthe annular recess and having at the oppositeend a series of segments spaced apart; the spaces being greater in widththan the chasers; each segment having a screw thread thereon meshingwith the teeth on the chasers; a transverse opening at the outer end ofthe body portion back of each chaser; a block mounted in each openingand beveled at the 'rear; a screw threaded ring adapted to the screwthreaded portion of the body and having a beveled surface engaging thebeveled surface of the blocks, so that, upon turning the ring, theblocks will force the chasers toward the center of the body.

11. The combination in a cutting device, of a body portion havinginternal longitudinal grooves; cutters mounted in the grooves; and alocking device located within the body portion and bearing against thetoothed edge of the cutters for retaining said cutters in position.

Intestimony whereof, I have signed my name to this specification, in thepresence of two subscribing witnesses.

JOHN R. SAYLOR.

Witnesses:

WM. E. SHUPE, WM. A. BARR.

Copies of this patent may be obtained for five cents each, by addressingthe Gommissioner of Patents,

Washington, D. G.

